Teikoku Kagekidan

I don't believe at all that there's a real imbalance among protagonists in anime, with female protagonists being more common, and that this imbalance is significant. Such an imbalance could negate my point about popularity, but as it is, it remains relevant.

From a technical point of view, saying that your statement is incorrect in relation to other genres does not equal saying that there is no imbalance in other genres in favor of female protagonists, or even that there is no imbalance in favor of male protagonists in other genres. However, your statement is true not only in relation to shonen, but also to some other genres.